1. Field of the Invention
The present invention relates generally to a safety device which cuts off the water supply to a house or building in the event of overly high water consumption due to a leak, break or open faucet in the plumbing of a house or building.
2. Description of the Related Art
Other than a fire, perhaps the most catastrophic type of damage which can occur to a home or other building is damage due to water leakage from a broken or badly leaking water line. Since water supply lines may run throughout a house or other building, a leak may occur in the heart of the house or other building, and may result in extensive damage both to the structure and to the contents prior to the water supply being manually shut off.
The main causes of runaway water leakage are ruptured pipes, tubes or fittings; faulty washing machine hoses, water heaters, supply lines and other plumbing equipment; rusty or aging components, electrolysis, poor installation practices, poor quality materials, frozen pipes, tubes or hoses, earthquake activity and pressure surges. With so many different factors that can create plumbing failures and runaway water leaks, one can readily realize the need for a fluid shutoff safety device. Flooding in a home or other building brings water damage resulting in extensive destruction and expense. Massive difficulties ensue in the wake of interior structural flooding as families and businesses must contend with problems including substantial loss of time, money and the home, office or other building involved.
In the prior art, there exists a number of devices which are designed to control flow and to act as a shutoff in the event of a leak. These devices generally fall into two major categories, namely the shock operated type and the flow or pressure operated type. The shock operated device is designed to shut off flow in the event of a major shock such as that of an earthquake or the like. Examples of such devices are found in Lloyd, U.S. Pat. No. 3,747,616, and Mueller, U.S. Pat. No. 3,768,497 and Pasmany, U.S. Pat. No. 4,091,831. These devices are all designed for use with gas lines and do not address the problem of breaks or leaks in the line downstream of the devices. In addition, the shock operated type of control valves do not address the problem of broken or leaking water or gas lines due to normal erosion or the possibility that someone has simply opened a faucet or line and has forgotten to close it.
The second approach, which causes a shutoff of flow in the event of an overly large flow rate or an excess pressure change across the device, is illustrated, for example, by Frager, U.S. Pat. No. 2,659,383, Bandemortelli, U.S. Pat. No. 4,522,229, and Quenin, U.S. Pat. No. 4,665,932. All three of these devices are designed primarily for industrial applications and are large, complex and expensive and therefore, inappropriate for use in a home or other relatively small building. A simpler valve control device designed to cut off the water supply to a house or building is described in U.S. Pat. No. 4,880,030 entitled "Safety Flow Control Fluid Shutoff Device." This device detects a downstream plumbing break or leak by sensing a water pressure increase within the valve. This increase in water pressure forces a piston to block the outlet of the device, thereby stopping flow through the device. It should be understood that the terms, "valve control device," "control valves" and "flood control devices or valves" as used herein, are synonymous and interchangeable.
Control valves which detect a high rate of flow have many drawbacks. With these types of control valves, undesired shut-offs may occur because of a high rate of flow under normal service conditions due to increases of water or gas consumption during a given period or increases in population in a water main's area, for example. Furthermore, if a break occurs, a great amount of water might run away before the predetermined value of rate of flow has been reached to effectuate a valve shut-off. Control valves which are pressure sensitive are also not reliable because there are many factors that can cause a change in water pressure, which does not necessarily mean that there is an overflow of fluid. For example, in a system where water mains are connected together in any number and one of these mains breaks, the pressure head decreases swiftly not only on the broken main but also on all the other mains and the respective control valves which are connected to these mains may unnecessarily close at the same time. Also, if a pressure sensitive control valve is located in a high place and the upstream length of the main is great, the pressure differences due to gravitational forces can cause variations in the shut-off parameters, leading to possible shut-offs which are unnecessary and inconvenient to customers as well as to water supply companies.
The prior art valve control devices described above do not address the problem of a faucet which has inadvertently been left open. There is no way for these devices to distinguish this situation from everyday normal water use. Furthermore, these prior art valve control devices are unreliable in detecting gradual leaks that create gradual changes in pressure which may be undetectable by the device.
Thus, there clearly exists a need for an improved valve control device that overcomes the deficiencies of the prior art devices and reliably eliminates the potential hazard of flooding. Moreover, such a device is needed which has the capability to measure the volume of a continuous flow of fluid and shut the fluid flow off when a preset maximum volume limit has been reached. Further, an improved flood control valve is needed that can be set for different fluid volumes depending on the size of the building or home or water usage in a particular operation. This would allow a user to advantageously change the volume of fluid which is used during one session to meet the fluid consumption demands of his or her particular home or building.